Effect of degree of separation of visual-auditory stimulus and eye position upon spatial interaction of vision and audition.

Subjects were exposed to a visual and to an auditory stimulus that differed spatially in laterality of origin. The subjects were observed for visual biasing of auditory localization (the momentary influence of a light on the spatially perceived location of a simultaneously presented sound) and for auditory aftereffect (a change in perceived location of a sound that persists over time and is measured after termination of the visual stimulus). A significant effect of visual stimulation on auditory localization was found only with the measure of bias. Bias was tested as a function of degree of visual-auditory separation (10/20/30 degrees), eye position (straight-ahead/visual stimulus fixation), and position of visual stimulus relative to auditory stimulus (left/right). Only eye position proved statistically significant; straight-ahead eye position induced more bias than did fixation of the visual stimulus.